The elements which give the greatest number of oxidation states and the highest oxidation states occur in or near the middle of the transition series . Manganese ($\text{Mn}$), located in the middle of the 3d series, has the electronic configuration $[\text{Ar}] 3d^5 4s^2$. By involving all of its five $3d$ and two $4s$ electrons in bonding, it exhibits a maximum oxidation state of $+7$ . On the other hand, Chromium ($\text{Cr}$) shows a maximum oxidation state of $+6$, Iron ($\text{Fe}$) shows up to $+6$ (though $+2$ and $+3$ are most common), and Vanadium ($\text{V}$) shows up to $+5$ .